It is known in the art to provide a liquid crystal device constructed by placing a sealing member between two substrates and sealing a liquid crystal layer therebetween, wherein provisions are made such that, during transmission of visible light through the liquid crystal device, the visible light transmittance of both the liquid crystal device and its sealing frame is set high, while at the same time, the difference in haze value between the liquid crystal device and the sealing frame is held small (for example, patent document 1).
The above liquid crystal device can be made completely transparent, including its sealing frame, and thus it is possible to provide a liquid crystal device having an excellent exterior design, since its external appearance is not impaired even if the sealing frame is not covered with a case or the like. This makes it possible to use the liquid crystal device applications such as show windows, bulletin boards, automotive instrument panels, etc., that can display characters and patterns.
FIG. 19 is a cross-sectional view of the prior art liquid crystal device disclosed in patent document 1.
As shown in FIG. 19, the liquid crystal device 200 includes a pair of first and second transparent substrates 201 and 202, a sealing member 204 placed therebetween, and a liquid crystal layer 203 sealed within a space enclosed by the sealing member 204.
In the liquid crystal device 200, the liquid crystal layer 203 is a composite layer made of a liquid crystal and a curing material, theoretically has a high light transmittance, and is suitable for such applications as show windows, bulletin boards, etc., that can display characters and patterns. The first transparent substrate 201 has a larger surface area than the second transparent substrate 202, and the liquid crystal layer 203 is formed only in an area that needs to be provided with the function of displaying characters and patterns.
A plurality of transparent electrodes 210 are formed in a stripe pattern on the inner surface of the first transparent substrate 201. Similarly, a plurality of transparent electrodes 210 are formed in a stripe pattern on the inner surface of the second transparent substrate 202. The plurality of transparent electrodes 210 on the inner surface of the first transparent substrate 201 and the plurality of transparent electrodes 210 on the inner surface of the second transparent substrate 202 together form a matrix of electrodes. An insulating film and an alignment film, not shown, are formed on each electrode array 210.
Cell gap is controlled by uniformly dispersing spacers 206 throughout the space enclosed by the first and second transparent substrates 201 and 202 and sealed by the sealing member 204. The sealing member 204 is disposed between the first and second transparent substrates 201 and 202 in such a manner to form a frame around the periphery of the first transparent substrate 201. The first and second transparent substrates 201 and 202 are bonded together by the sealing member 204.
If the selected sealing member 204 is tinted, or the visible light transmittance of the material is low, the sealing member may become visible, which may degrade the external appearance or could lead to an exterior design problem. When using the liquid crystal device 200 in such applications as show windows, bulletin boards, automotive instrument panels, etc., there are cases where the portions bonded by the sealing member 204 may not be able to be neatly hidden by means of a frame or a case. According to the method proposed in patent document 1 to solve such problems, the visible light transmittance of the sealing member 204 is set to 70% or higher, or the difference between the haze value of the sealing member 204 and the haze value of the liquid crystal layer 203 during transmission of visible light is held to within ±3%.